invlpg – Premature Optimization is Fun Sometimes

kept by eddie jun 08

A developer describes optimizing a 12KB ping-monitoring ring buffer down to 4KB using bitfields and tagged unions purely for enjoyment, despite the application not being memory-constrained.

Todd C. Miller – Sudo maintainer for over 30 years
Todd C. Miller, the long-time maintainer of the critical sudo utility, is seeking sponsorship to continue development and maintenance.
also on OpenBSD, #linux, #developer-tools
JP's Website · 2026-08-22 · Why aren't my two Cortex-A9 cores cache coherent?
On a Terasic DE0-Nano-SOC, two Cortex-A9 cores cannot see each other's memory writes despite enabled MMU, caches, and SCU, revealing a cache coherence failure.
also on #performance, #linux, #developer-tools
Pitfalls of Benchmarking on Modern Systems
Benchmarking modern systems is unreliable due to JIT optimizations, OS scheduling, hardware variability, and environmental factors, requiring careful controls or many runs to understand true performance.
also on #performance, #linux
The occasional `ECONNRESET`
Closing a TCP socket with `shutdown(RD_WR)` or `close()` can cause `ECONNRESET` errors for the peer because data still in flight may be discarded before the receiver finishes reading.
also on #linux, #programming-languages